Electrical connector

ABSTRACT

An electrical connector of the &#39;&#39;&#39;&#39;butt&#39;&#39;&#39;&#39; contact type having a fixed receptacle and a movable plug. The receptacle comprises a shell which receives two insulators. The insulators house a set of contact elements comprising a fixed piece and a movable piece. The fixed piece is made up of a solder termination and a pin which cooperates with the slotted socket of the movable piece. The latter is subjected to the action of a spring. The plug of the connector includes an insulator which holds another set of fixed contact elements. Locking of the plug and receptacle is is achieved by bayonets housed in the plug.

United States Patent [191 Gaspar et al.

[ ELECTRICAL CONNECTOR [75] Inventors: Claude E. Gaspar, Mondouzil;

Christian Adrien, LUnion; Roman J. Komorowski, Colomiers, all of France [73] Assignee: International Standard Electric Corporation, New York, NY.

[22] Filed: Feb. 1, 1973 [21] Appl. No.: 328,680

[52] US. Cl. 339/90 R, 339/95 R, 339/187 [51] Int. Cl Hlr 13/54 [58] Field of Search 339/45, 48, 49, 88, 90, 339/94, 95, 184, 185, 187

[ 6] References Cited UNITED STATES PATENTS 3,534,320 10/1970 Rushing 339/ M 2,677,811 5/1954 Anderson et a1... 339/184 M 2,986,613 5/1961 Figueira 339/94 R 3,360,764 12/1967 Bac 33 /45 M Apr. 16, 1974 3,719,918 3/1973 Kerr 339/ R FOREIGN PATENTS OR APPLICATIONS 589,344 12/1933 Germany 339/184 R 1,498,342 9/1967 France 339/88 R Primary Examiner-Joseph l-l. McGlynn Attorney, Agent, or Firm-Thomas L. Peterson [5 7] ABSTRACT An electrical connector of the butt contact type having a fixed receptacle and a movable plug. The receptaclecomprises a shell which receives two insulators. The insulators house a set of contact elements comprising a fixed piece and a movable piece. The fixed piece is made up of a solder termination and a pin which cooperates with the slotted socket of the movable piece. The latter is subjected to the action of a spring. The plug of the connector includes an insulator which holds another set of fixed contact elements.

Locking of the plug and receptacle is is achieved by bayonets housed in the plug.

7 Claims, 11 Drawing Figures Pmmcmm 16 m4 3.805216 SHEET 3 [IF 6 PATENTEDAPR 16 m 3L805L216 SHEET 5 [IF 6 ELECTRICAL CONNECTOR BACKGROUND OF THE INVENTION The present invention relates to improvements in electrical connectors and, more particularly, to connectors used in telecommunications for low frequency communication portable equipment.

This type of connector is well known and is widely used, more particularly, in radio telecommunication equipment used for military purposes. Generally, in this kind of connector, the electrical connections are not established by contacts obtained by means of male pins being inserted into female sockets but by pressing end to end contact pieces arranged in the two elements constituting the connector, this pressureresulting from the effect of springs acting upon the contact pieces. Another characteristic of this category of connectors concerns the self-cleaning of the contacts. Indeed, the environment in which the connectors in question are used is not always favorable to obtaining good electrical connections. Also, during the operation which consists in coupling the two parts of the connector, steps are taken to enable a friction between the ends of the contact pieces which gives a cleaning of the surfaces between which the end to end or butt contact must be established.

Such connectors have generally given good results in their application. Nevertheless, such connectors present the serious drawback of being heavy and bulky, a drawback the consequential effects of which are all the more felt as technological advance enables reducing progressively the size of equipment in which the connectors are used.

Moreover, in military applications, as stress is laid on the importance of communications in the coordination of strategic movements, radio-telecommunication equipment becomes less static and must be more and more movable. When the stage of the individual equipment is reached, i.e., equipment carried by the man, it is obvious that these problems of weight and space become all important and it is no longer possible to use existing connectors.

An object of the present invention is to obviate such drawbacks and to construct a miniature and light weight connector.

Nevertheless, such a connector must have characteristics, in spite of its miniaturization, equivalent to those existing connectors. The reduction of size of the connector presents a series of problems for, on account of its use in portable military equipment, it can be easily imagined that the connector of the invention will be subjected to all sorts of aggressions according to its intended use. Snow, rain, and moisture present problems of water-tightness, of resistance to corrosion and of electrical quality of the contact. As the connector is not sometimes permanently coupled, sand, earth or other elements require close attention from the user. The connector must be able to accumulate a certain quantity of external elements without being prejudicial to its quality of contact and to its electrical characteristics.

Another object of the invention is to satisfy such criteria in spite of strict conditions of use.

SUMMARY OF THE INVENTION According to the invention, there is provided a connector'having for its fixed element, the receptacle, a shell receiving two insulating pieces made integral after being assembled by a bonding operation. These two insulating pieces the front insulator and the back insulator are respectively used for housing the movable part and the fixed part which constitute each piece of the contact of the connector receptacle. The fixed part is mounted in the back insulator to present on one side of this insulator a solder termination which enables soldering to a conductor and on the other side a pin for cooperating with the movable part of the contact piece. The movable part is arranged in a chamber on the front insulator. The movable part comprises a cylindrical body, one end of which is used for the butt contact and the other end provides a slotted socket for slidably receiving the pin of the fixed part. A spring is arranged around the socket and the pin to push the movable part towards the outside of the connector. An elastic seal is arranged between a flange on the movable part and a shoulder in the chamber in order that its compression may ensure a sealing of this chamber so that the socket and the pin of the contact pieces are protected against external agents.

The other element of the connector, i.e., the removable element, the plug, also comprises a shell having an insulator into which there are mounted the contact pieces of the plug. The contact pieces are fixed in the insulator and present on one side of the insulator a solder termination enabling soldering to a conductor and .on the other side a cylindrical body the end of which is used for the butt contact. The length of this cylindrical body is relatively great in order that the volume of the chamber in which it is positioned may be suffciently great to permit the presence of a certain quantity of external agents without disturbing the operation of the connector.

The locking of the plug in the receptacle is accomplished by a system of coupling pins, the pins being carried by the plug. To avoid errors in positioning of the plug in the receptacle, the pins and the slots provided for receiving them on the receptacle are positioned in an asymmetric way so that there may be only one position which permits the plug to be inserted and locked onto the receptacle. Such an arrangement is used to allow for polarizing when the plug is mounted in the receptacle and coupled to it.

BRIEF DESCRIPTION OF THE DRAWINGS view of the connector after locking the plug in the re- 7 ceptacle; and

FIGS. 9 to 11 illustrate the self-wiping process of the contact pieces of the connector of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Reference is now made to FIG. 1, showing the connector of the invention represented in the assembled position, i.e., in the position which enables establishing an electrical connection between the solder terminations 1 of the receptacle 2 and the solder terminations 3 of the plug 4.

The receptacle 2 is the fixed part of the connector. It is fixed to a support 5 which can be a wall belonging to telecommunications equipment by means, for instance, of screws 6 and nuts 7. In this way, the solder terminations are protected by the equipment and they enable the normal soldering of the'conductors of a connection cable (not shown).

Plug 4 is removable from the receptacle. It is desirable that the mechanical stresses due to the plug handling not be absorbed by the solder terminations 3 alone. Therefore, the conductors of the connection cable are normally soldered on the solder terminations 3 and are also held mechanically by a heat shrinkable plastic sheath 8 which encloses the back part of the plug as indicated in phantom in FIG. 1, the back part enabling the tightening of a possible grounding shield as it will be subsequently seen.

The receptacle 2 is formed with wings 9 and 10 having openings 11 and 12 therein enabling the insertion of the screws 6, the function of which is to enable the fixing of the receptacle on the support 5.

The receptacle 2 is essentially constituted by a metallic shell 13 which is used as a housing for a back insulator l4 and a front insulator 15. It will be noted that the part 16 of the shell 13 on the left of the wings 9 and 10, as viewed in FIG. 2, is formed with slots 17 for locking of the plug as will be described subsequently. This part 16 is itself reduced to form a cylindrical wall 18. The external diameter of this wall and the chamfer 19 which it presents at its free end are provided to cooperate with corresponding elements of the plug 4 as will be described subsequently, these steps being taken to establish the metallic connection between the contact elements 20 in the receptacle and the corresponding contact elements of the plug under the best possible conditions.

The contact elements 20 are constituted each by two main pieces, on the one hand, a fixed part the central part of which is sunk into the back insulator 14 and the respective ends of which are formed by the solder termination 1 and the pin 22; on the other hand, a movable part comprising a slotted socket 23 having a contact end 24.

The movable part of each contact element is housed in the front insulator 15. For that purpose, this insulator presents for each contact element two cylindric chambers 25 and 26 which are joined by a countersunk surface 27. These two chambers 25 and 26 have diameters which slidably receive a flange 28 on the movable part of the contact element and the contact end 24, respectively. When the front insulator is properly positioned in the shell 13, a shoulder 29 therein abuts against a shoulder 29a on the shell. The movable parts of the contact elements are inserted into the respective chambers 25, 26 from the back face 30 of the front insulator. A compression spring 31 is mounted in chamber 25 around the slotted socket 23.

The forward end of the spring abuts against the flange 28.

The fixed part of each contact element is sunk into the back insulator 14. The molding of this insulator is formed around the central part 21 of these fixed parts. It will be noted that this central part 21 comprises several flanges 32, 33, 34 and 35. In addition to their mechanical function which consists of enabling a better anchoring in the insulator 14 than a purely cylindric part would enable, these flanges provide grooves which constitute a tightness barrier. The leaking path presented by the periphery of the central part 21 is increased, this contact surface being larger between the insulator l4 and the metallic part 21 making more difficult the progress of possible moisture infiltration from the external face 36 of the receptacle.

It will be also noted that the flange 35 is sunk only one half of its thickness into the body of the insulator 14, its external diameter being of the same value as that of the chamber 25. In that way, the coaxial alignment of the respective movable and fixed parts of the contact element is made easier, the free part of the flange 35 entering the chamber 25 at the end of the insertion of the pin 22 into the socket 23. Moreover, it can be noted that this insertion is limited and that it stops as soon as the faces 30 and 37 of the insulators 14 and 15 are in contact. As a matter of fact, these faces are covered by a film of a bonding material 38 which enables a strong sticking on the one hand, of the insulator 15 with the metallic shell 13 and, on the other hand, of the insulator 14 with the insulator 15. This same material 38 enables a perfect tightness chiefly against moisture which could infiltrate between the shell 13, the back face of the insulator 15 and the front face of the insulator 14.

It is noted that before the insertionof the movable part of the contact element into the chambers 25 and 26 in the insulator 15, a peripheral seal 39 made of an elastic material is arranged between the flange 28 and the contact end 24. When the different parts of the receptacle are assembled, as illustrated by FIG. 2, the spring 31 associated with each contact element is pressed between the flanges 35 and 28. As the flange 35 is fixed, the action of the spring 31 will be exerted on the flange 28 of the movable part of the contact element, an action which will result in a compression of the peripheral seal 39 by the flange 28. The peripheral seal will be consequently applied against the countersunk surface 27 and thus will permit the sealing of the chamber 25 by preventing any possibility of access to external agents moisture or other agents which could try to penetrate through the space left free between the end of contact 24 and and the wall of its chamber 26 and adversely affect the characteristics of the contact existing between the socket 23 and the pin 22.

In addition to its bonding due to the material 38, the back insulator 14 is enclosed in the cover 13 by means of a crimping of the extreme part 40 of said shell. This crimped part has a slot 41 therein into which fits a projecting part 42 on the back insulator 14, as best seen in FIG. 3. The latter performs a double function. On the one hand, it contributes to prevent the possible rotation of the insulator 14 in the shell 13; on the other hand, it enables the polarizing, i.e., it enables positioning of the insulator 14 in the receptacle according to a predetermined position and not in another position.

It will be also noted in FIG. 3 that the bevelled part 43 of the solder terminations is always directed toward the outside which makes easier the soldering of the conductors inserted respectively into these solder terminations which are identified by letters A-G. It will be noted that the central. solder termination bearing the reference G can be made longer than the others (as indicated on FIG. 2), the aim of this arrangement being also to make the soldering operation easier.

Reference is now made to FIG. 4 which shows the plug of the connector of the invention. This plug is essentially made up of a shell 44, an insulator 45 and fixed contact elements 46.

The shell 44 comprises a ring 47 the external knurling of which makes the gripping and the handling of the plug easier. Pins 48 are forced into openings in the ring 47 so that their inner ends may project into a cylindrical bore 50 in shell 44. These pins enable locking of the plug in the receptacle as will be subsequently described. I

The cylindrical bore 50, the diameter of which is determined by the diameter of the part 16, is in communication with a second cylindrical bore 51, the diameter of which is defined by the diameter of the cylindrical wall 18. These two bores 50 and 51 are joined by a chamfer 52. Another chamfer 53 is provided in the bottom of the bore 51. It will be subsequently noted how the chamfer 52 makes the centering easier when the plug is mounted on the receptacle of the connector.

An annular groove 54 in shell 44 opens into bore 51. The groove receives an O ring seal 55 the internal diameter of which is smaller than the diameter of the bore 51.

The shell 44 comprises also an external circular groove 56 which separates the knurled ring 47 from a back notched part 57. This part comprises circular grooves 59 the function of which is to make easier the anchoring of the heat shrink boot 8 mounted on the back part of the casing 44, as indicated in FIG. 1 in phantom lines. The notches provided by the grooves 59 give to the boot a better resistance to tension it could undergo and thus increase its anchoring around the back part 57. It is to be noted that these grooves 59 have also the advantage of enabling a good contact between the metallic braid of a shielded cable (not shown), a braid which would be tightened by a grip in the groove 56. In some cases, the back part can comprise a knurling instead of the circular grooves 59.

Each contact element 46 is constituted by an end 60, the solder termination 3 and a central part 61. This central part is sunk into the insulator 45 and comprises flanges 62, 63, 64 and 65 which have the same function as the flanges 32 to 35, i.e., they increase the distance that a possible infiltration of moisture must cover from the face 66. It will be noted that the solder terminations 3, like the solder terminations 1, (FIG. 2) have their bevelled faces 67 directed outside to make the soldering operation easier, the central solder termination having a greater length than the length of the other solder terminations for the same reasons of soldering ease.

In the same way as for mounting the parts constituting the receptacle, a sealing material 69 which enables a strong sticking and a perfect tightness between the insulator 45 and the metallic shell 44 is used. This insulator 45 has a projecting part 70 which fits into a notch 71 of the back part of the shell 44. This part has the same function as that of the part 42. It makes easier the positioning of the insulator 45 and of the contact elements 46 in a predetermined position and contributes to prevent any possibility of rotation of this insulator. It will be finally noted that a circular crimping 72 on the shell 44 forms a retention for the insulator 45.

The description will be now continued by explaining how the receptacle of FIG. 2 and the plug of FIG. 4 are assembled.

Referring to FIG. 5, it can be seen that the knurled ring of the plug has a mark 73 which can be obtained by a trace of paint made in one of the grooves of the knurling. In FIG. 6, it can be noted that the receptacle also has a mark which is presented in the shape of a color point 74. When the plug is mounted on the receptacle, the locking is made easier by aligning these two marks 73 and 74. Indeed the contact elements of the receptacle and of the plug must be set in a predetermined way for mating. That is the reason why the slots 17 made in the part 16 to house the locking pins 48 are not distributed in a symmetric way but according to the arrangement of these pins in the plug. FIG. 7 is an end view of the plug represented in FIG. 5 and it can be seen that the pins have been arranged so that there is between the pins 75 and 76 and between pins 76 and 77. It can be noted that these pins are respectively shifted an angle a the value of which is 13 in the example of the invention with respect to the contacts which enables inserting the pins into the slots 17 when the marks 73 and 74 are in alignment and thereafter allowing the plug to make a rotation of about 13. At this time, the pins are locked, as it will be seen subsequently, and the contact elements are respectively in butt position.

The assembling process itself will be now described with reference to FIGS. 2, 4 and 8, FIG. 8 showing the connector elements in the position in which they are at the end of said coupling process.

When the plug is mounted on the receptacle of the connector, the cylindrical wall 18 first penetrates easily into the housing as the diameter of the bore 50 is greater than the diameter of the wall 18. Rough centering of the plug in the receptacle is obtained due to the action of the chamfer 52 of the plug and of the chamfer 19 of the receptacle. When the chamfer 52 has slid past the chamfer 19, the centering of the two parts is perfect and the bore 51 starts sliding around the wall 18. Simultaneously, the chamfer 19 penetrates inside the O ring seal 55 and, progressively, causes a deform'ation of this seal by enlarging its internal diameter. This deformation results in a compression of the seal against the walls and the bottom of the groove 54 and against the external surface of the wall 18. This enables the 0" ring seal 55 to perform its function of tightness to prevent possible infiltration of external agents such as a moisture which could occur because of the slight space mechanically necessary for mounting of the plug on the receptacle and existing between, on the one hand, the bore 50 and the shell 13 and, on the other hand, the bore 51 and the wall 18.

As movement of the plug on the receptacle continues, the seal 55 will slide along the cylindrical wall 18 and the ends 49 of the pins 48 will penetrate into the locking slots 17 of the receptacle, it being understood that the marks 73 and 74 (FIGS. 5 and 6) of the knurled ring and of the receptacle have been aligned as previously explained.

Then, the ends 60 of the fixed contact elements will abut against the ends 24 of the movable contact elements and, as the mounting process continues, the ends 60 push back the ends 24 into their respective holes 26. As the ends 24 are each integral with the flange 28 and the socket 23, the latter are moved inside the chamber 25 in such a way that the flange 28 compresses the spring 31, the slotted socket 23 sliding around the pin 22. It will be noted that, at this moment, the seal 39 stops being pressed against the surface 27 and is drawn into the chamber 25 simultaneously with the end of contact 24 with which it is integral. The sealing which the seal 39 provided and which was necessary before mounting the plug in the receptacle no longer exists but protection against external agents is always present as the seal 55 provides this protection.

At a given stage of the progress of the plug on the receptacle, the ends 49 of the locking pins 48 abut against the bottom 79 of the slots 17. To clarify this part of the description, one of the ends 49 of a pin 48 has been represented in FIG. 2 by a dotted line and a hatched surface in the positions in which it is during the locking operation. A rotary motion is then imparted to the knurled ring 47 of the plug which determines the positioning of the end 49 in the direction of arrow F1. When the end 49 enters into contact with the bottom 80 of the slot 17, the knurled ring of the plug is released.

At this moment, the springs 31 are compressed to their optimum value as the plug cannot progress further on the receptacle from the moment when its pins have abutted against the bottom 79 of the locking slots. If there is no more action on this plug, the opposite force of the springs 31 will be exerted against the flanges 28 and said flanges will transmit a force to the contact ends 60. As these ends are in a fixed position in the insulator 45, the whole plug will move back. This backward movement corresponds to a similar movement of the end 49 of the locking pins, i.e. to a movement in the direction of arrow F2, till the end 49 abuts against the edge 81 of the slot 17. The ends 24 of the movable contact elements will then exert a permanent pressure which is the contact pressure against the ends 60 of the fixed contact elements as there is a free space 82 between the seal 39 and the surface 27. However, when the plug and receptacle are separated, under the action of the spring 31, the movable contact element is pushed back toward the outside of the receptacle and the seal 39 is pressed against the surface 27 as seen in FIG. 2.

By examining again FIG. 2, it is seen that if the connector must be decoupled, it is necessary to impart to the plug a motion which enables the ends 49 to follow the direction opposite to the direction of arrow F2, then a rotary motion reversely to the direction indicated by arrow Fl, the aim of it being to escape the lip 83. This lip is not situated in the same plane as the edge 81 of the slot 17 so that it will prevent any accidental unlocking which would result from an excessive rotation being exerted in the direction of arrow F3 for, to unlock, it is required that the application of a second force be exerted in opposition to arrow F2.

With reference to FIG. 8, it is noted that the volume of the chamber in which there is established the contact between the ends 60 and 24 is relatively great, this volume being dependent upon the length of the end 60. This arrangement is provided because the plug can be in contact with elements such as sand or dust, for instance, when the connector is not coupled. In that way, if these external elements are still present after coupling the plug on the receptacle, they are distributed in the relatively large volume of the chamber provided by the cylindrical wall 18 and thus cannot disturb the operation of the connector by causing, for instance, a sufficient accumulation to establish short-circuits between the contact ends.

Moreover, according to the medium from which they originate, these external elements can produce a strong moisture. It is that reason why a certain length has been provided for the end in orderthat possible moisture may have to cross this distance before reaching the contact surface 84.

In the description of the locking process, it has been noted that a rotary motion was imparted to the plug. Now, the fixed contact elements are integral with the plug so that they may take part in this rotary motion. This arrangement has been used to enable the selfcleaning of the contact surfaces when the two partsof the connector are coupled.

This self-cleaning will be now described with reference to FIGS. 9, 10 and 1 1. FIG. 9 indicates the respective positions of the contact ends 60 and 24 of two fixed and movable contact elements before the locking operation, i.e., when the plug has been completely engaged onto the receptacle before imparting to it the rotary motion. It can be noted that the contact 'ends 60 and 24 are not exactly aligned and the contact is established on a part near the periphery of the face 85. This fact is illustrated by FIG. 11 and by the respective positions of the contact end 24 and of the contact end 60 represented by a dotted line.

FIG. 10 indicates the respective positions of the contact ends 60 and 24 after the rotary motion for the locking has been imparted to the plug. It can be then noted that the contact is established on a part also near the periphery of the face 85 but that this part is diametrically opposite compared with the part as seen in FIG. 9. This is also illustrated by FIG. 11, the position of the end of the fixed contact being indicated by the dashdotted circle bearing the reference 60'.

It can be noted that the rotary motion which enables locking the plug on the receptacle determines, at the level of the contact surface between the fixed and movable contact elements, a movement of the contact point a distance almost equal to the distance of the diameter of the face 85. This movement results in friction between the faces in contact with the ends 60 and 24, which causes the self-cleaning of the contact area and thus ensures the optimum electrical characteristics for the contact finally established.

It will be, however, noted that this friction will not exist for the ends of the central contact elements such as the one bearing the reference G in FIG. 3. For this reason, the central contact element has been slightly decentered in each insulator 14 (FIG. 2) and 45 (FIG. 4) in order that there may be, during the locking operation, a sufficient friction between these elements to enable satisfactory contact self-cleaning.

What is claimed is:

1. An electrical connector of the butt contact type comprising:

plug and receptacle connector members each having at least one contact therein adapted to engage upon mating of said members;

front and rear insulators in said receptacle connector member, said front insulator having a chamber therein for said contact;

said receptacle connector member contact including a movable part and a fixed part, said movable part being slidably mounted in said chamber and said fixed part being fixedly mounted in said rear insulator;

said fixed part having one end extending into said chamber;

said movable part including a cylindrical contacting portion and a slotted socket portion separated by an outwardly extending flange, said slotted socket portion slidably receiving said one end of said fixed P means biasing said contacting portion of said movable part outside said front insulator toward said plug connector member;

said plug connector member comprising a shell having an insulator therein;

said plug connector member contact being mounted in said plug insulator and extending forwardly thereof for butt contact with said receptacle connector member contact; and

means on said plug and receptacle connector members for determining the polarization of said members and, after mating thereof, locking said members together.

2. An electrical connector as set forth in claim 1 wherein:

the other end of said fixed part of said receptacle connector member contact extends beyond the outer surface of said rear insulator for connection to an electrical connector;

said one end of said fixed part comprising a pin; and

the central portion of said fixed part being embedded in said rear insulator, said central portion having at least one outwardly extending flange thereon.

3., An electrical connector as set forth in claim 11 wherein:

a bore is formed in said front insulator coaxial with said chamber and communicating said chamber to the exterior of said front insulator, said bore having a cross-section less than that of said chamber providing therebetween a rearwardly facing shoulder;

said flange on said movable part being located in said chamber behind said shoulder;

a resilient sealing member surrounding said cylindrical contacting portion between said movable part flange and said shoulder; and

said biasing means comprises a compression spring between said movable part flange and said rear insulator.

4. An electrical connector as set forth in claim 1 wherein:

said shell of said plug connector member has a bore therein receiving said insulator, said insulator being positioned behind the front of said shell to define an open cavity;

said shell of said receptacle connector member being slidably mounted in said cavity;

an annular groove in said plug connector member shell opening into said cavity; and

a sealing ring positioned in said groove and having an inner diameter less than the diameter of said cavity,

said sealing ring being in sealing engagement with said receptacle connector member shell.

5. An electrical connector of the butt contact type comprising:

plug and receptacle connector members each having at least one contact therein adapted to engage upon mating of said members;

front and rear insulators in said receptacle connector member, said front insulator having a chamber therein for said contact;

said receptacle connector member contact including a movable part and a fixed part, said movable part being slidably mounted in said chamber and said fixed part being fixedly mounted in said rear insulator;

said fixed .part having one end extending into said chamber and slidably mating with said movable part;

means biasing said movable part outside said front insulator toward said plug connector member;

said plug connector member comprising a shell having an insulator therein;

said plug connector member contact being mounted in said plug insulator and' extending forwardly thereof for butt contact with said receptacle connector member contact; and

means on said plug and receptacle connector members for determining the polarization of said members and, after mating thereof, locking said members together, said polarizing and locking means comprising:

a plurality of pins asymmetrically mounted on said plug connector member shell and extending into the interior of said shell;

a number of L-shaped slots in said receptacle connector member shell equal to the number of said pins and disposed in a corresponding asymmetric pattern for receiving said pins, a first leg of each L- shaped slot opening at the front of said shell and extending axially of the shell and the second leg of each slot extending circumferentially of said shell;

said plug connector member contact being sufficiently long so that when said pins are completely inserted into said first legs of said slots, said plug connector contact will engage and pushsaid movable part of said receptacle connector member contact rearwardly; and

rotary motion of said plug connector member with respect to said receptacle connector member causing said pins to move into said second legs of said slots, said second legs of said slots being sufficiently wide so that said biasing means will push said movable part forwardly, hence causing backward movement of the contact in said plug connector member, and of said plug connector member itself, until said pins abut the forward edges of said second legs of said slots.

6. An electrical connector as set forth in claim 5 wherein:

before locking of said plug and receptacle connector members when said pins are completely inserted into said first legs of said L-shaped slots, the contacts of said members are slightly misaligned and engagement therebetween is established in an area near the periphery of the face of said contacts; and

the rotary motion imparted to said plug connector member causing said engagement to occur near said periphery but in an area diametrically opposite to said first-mentioned area, said rotary motion causing a wiping action between the faces of said contacts.

7. An electrical connector of the butt contact type comprising:

plug and receptacle connector members each having at least one contact therein adapted to engage upon mating of said members;

the contact in one of said connector members being fixed and the contact in the other of said connector members being movable in the direction toward said one connector member contact;

means biasing said movable contact toward said fixed contact for butt contact therebetween; and

means on said plug and receptacle connector members for determining the polarization of said members and, after mating thereof, locking said members together, the locking of said plug and receptacle connector members by said polarizing and locking means being effected by relative rotary motion between said members, the contacts of said respective connector members being slightly misaligned upon initial mating but before the locking of said members, and said rotary motion causing a wiping action between the faces of said contacts. 

1. An electrical connector of the ''''butt'''' contact type comprising: plug and receptacle connector members each having at least one contact therein adapted to engage upon mating of said members; front and rear insulators in said receptacle connector member, said front insulator having a chamber therein for said contact; said receptacle connector member contact including a movable part and a fixed part, said movable part being slidably mounted in said chamber and said fixed part being fixedly mounted in said rear insulator; said fixed part having one end extending into said chamber; said movable part including a cylindrical contacting portion and a slotted socket portion separated by an outwardly extending flange, said slotted socket portion slidably receiving said one end of said fixed part; means biasing said contacting portion of said movable part outside said front insulator toward said plug connector member; said plug connector member comprising a shell having an insulator therein; said plug connector member contact being mounted in said plug insulator and extending forwardly thereof for ''''butt'''' contact with said receptacle connector member contact; and means on said plug and receptacle connector members for determining the polarization of said members and, after mating thereof, locking said members together.
 2. An electrical connector as set forth in claim 1 wherein: the other end of said fixed part of said receptacle connector member contact extends beyond the outer surface of said rear insulator for connection to an electrical connector; said one end of said fixed part comprising a pin; and the central portion of said fixed part being embedded in said rear insulator, said central portion having at least one outwardly extending flange thereon.
 3. An electrical connector as set forth in claim 1 wherein: a bore is formed in said front insulator coaxial with said chamber and communicating said chamber to the exterior of said front insulator, said bore having a cross-section less than that of said chamber providing therebetween a rearwardly facing shoulder; said flange on said movable part being located in said chamber behind said shoulder; a resilient sealing member surrounding said cylindrical contacting portion between said movable part flange and said shoulder; and said biasing means comprises a compression spring between said movable part flange and said rear insulator.
 4. An electrical connector as set forth in claim 1 wherein: said shell of said plug connector member has a bore therein receiving said insulator, said insulator being positioned behind the front of said shell to define an open cavity; said shell of said receptacle connector member being slidably mounted in said cavity; an annular groove in said plug connector member shell opening into said cavity; and a sealing ring positioned in said groove and having an inner diameter less than the diameter of said cavity, said sealing ring being in sealing engagement with said receptacle connector member shell.
 5. An electrical connector of the ''''butt'''' contact type comprising: plug and receptacle connector members each having at least one contact therein adapted to engage upon mating of said members; front and rear insulators in said receptacle connector member, said front insulator having a chamber therein for said contact; said receptacle connector member contact including a Movable part and a fixed part, said movable part being slidably mounted in said chamber and said fixed part being fixedly mounted in said rear insulator; said fixed part having one end extending into said chamber and slidably mating with said movable part; means biasing said movable part outside said front insulator toward said plug connector member; said plug connector member comprising a shell having an insulator therein; said plug connector member contact being mounted in said plug insulator and extending forwardly thereof for ''''butt'''' contact with said receptacle connector member contact; and means on said plug and receptacle connector members for determining the polarization of said members and, after mating thereof, locking said members together, said polarizing and locking means comprising: a plurality of pins asymmetrically mounted on said plug connector member shell and extending into the interior of said shell; a number of L-shaped slots in said receptacle connector member shell equal to the number of said pins and disposed in a corresponding asymmetric pattern for receiving said pins, a first leg of each L-shaped slot opening at the front of said shell and extending axially of the shell and the second leg of each slot extending circumferentially of said shell; said plug connector member contact being sufficiently long so that when said pins are completely inserted into said first legs of said slots, said plug connector contact will engage and push said movable part of said receptacle connector member contact rearwardly; and rotary motion of said plug connector member with respect to said receptacle connector member causing said pins to move into said second legs of said slots, said second legs of said slots being sufficiently wide so that said biasing means will push said movable part forwardly, hence causing backward movement of the contact in said plug connector member, and of said plug connector member itself, until said pins abut the forward edges of said second legs of said slots.
 6. An electrical connector as set forth in claim 5 wherein: before locking of said plug and receptacle connector members when said pins are completely inserted into said first legs of said L-shaped slots, the contacts of said members are slightly misaligned and engagement therebetween is established in an area near the periphery of the face of said contacts; and the rotary motion imparted to said plug connector member causing said engagement to occur near said periphery but in an area diametrically opposite to said first-mentioned area, said rotary motion causing a wiping action between the faces of said contacts.
 7. An electrical connector of the ''''butt'''' contact type comprising: plug and receptacle connector members each having at least one contact therein adapted to engage upon mating of said members; the contact in one of said connector members being fixed and the contact in the other of said connector members being movable in the direction toward said one connector member contact; means biasing said movable contact toward said fixed contact for ''''butt'''' contact therebetween; and means on said plug and receptacle connector members for determining the polarization of said members and, after mating thereof, locking said members together, the locking of said plug and receptacle connector members by said polarizing and locking means being effected by relative rotary motion between said members, the contacts of said respective connector members being slightly misaligned upon initial mating but before the locking of said members, and said rotary motion causing a wiping action between the faces of said contacts. 